fix b frames + -mbd rd without -psnr (yes that was seriously buggy and probably hasnt been noticed as everyone who tested stuff used -psnr)

Originally committed as revision 7151 to svn://svn.ffmpeg.org/ffmpeg/trunk

tests/ffmpeg.regression.ref

@@ -79,10 +79,10 @@ stddev: 10.25 PSNR:27.90 bytes:7602176
 765722 ./data/a-mpeg4-thread.avi
 252d1e8cc1ee88eea693cebd6b4e7e53 *./data/out.yuv
 stddev: 12.32 PSNR:26.31 bytes:7602176
-670f6e540bcf504ccc72d41952cc401e *./data/a-mpeg4-Q.avi
-900488 ./data/a-mpeg4-Q.avi
-af59c063ed644c7dc4151a0a2debbddd *./data/out.yuv
-stddev:  5.69 PSNR:33.00 bytes:7602176
+851e2e80aa29b65378863e487e3e12ee *./data/a-mpeg4-Q.avi
+896048 ./data/a-mpeg4-Q.avi
+8db6ef5462b83220ddb008eba8f0d40c *./data/out.yuv
+stddev:  5.62 PSNR:33.12 bytes:7602176
 b8da412bd5421c6ac6fcb6c9caa261ae *./data/a-mpeg4-PSP.mp4
 407313 ./data/a-mpeg4-PSP.mp4
 ef45e577219460332bed428106f638a6 *./data/a-error-mpeg4-adv.avi

tests/rotozoom.regression.ref

@@ -79,10 +79,10 @@ stddev:  4.84 PSNR:34.42 bytes:7602176
 254304 ./data/a-mpeg4-thread.avi
 d6f1714d6fe1f969fc4ca416c6f8ba6c *./data/out.yuv
 stddev:  4.04 PSNR:35.98 bytes:7602176
-1c73de943d89a2f6e8a6efead02492e2 *./data/a-mpeg4-Q.avi
-166034 ./data/a-mpeg4-Q.avi
-b078f22c66083f0537bd3581509684d8 *./data/out.yuv
-stddev:  4.01 PSNR:36.05 bytes:7602176
+8a446c1335d17f385da07aaeec20f597 *./data/a-mpeg4-Q.avi
+166656 ./data/a-mpeg4-Q.avi
+0fc2c12ecd44e19408d9ad6fded2a9b8 *./data/out.yuv
+stddev:  4.00 PSNR:36.07 bytes:7602176
 29bdd2038570dc612f19eacfc4f9011a *./data/a-mpeg4-PSP.mp4
 321886 ./data/a-mpeg4-PSP.mp4
 d93e3d53110437db55e954a14fdd7c3a *./data/a-error-mpeg4-adv.avi